What the heck?

So I went ahead and got a zebra nerite snail and a tracked nerite snail for my 7 gallon aquarium, currently also inhabited with three shrimp and a betta. So far they have been very active in eating and moving, but I was watching the zebra and I noticed a small stream of particles coming out of his right hand side. Is he just pooping a lot, or is it something more serious, like his shell is degrading? I want to keep my snails and fish healthy!